3-Alkenyl-oxindole is a prominent structural motif found in a range of medicinally and biologically important compounds, as well as a number of natural products. This core is a part of many chemical compounds that were known to possess wide range of biological activities including anti-inflammatory, antiangiogenic, anticancer, tyrosine kinase A inhibition and cyclooxygenase inhibition. For example sunitinib as anticancer drug, Tenidap for the treatment of arthritis, Ziprasidone for schizophrenia and Ropinirole, a dopamine agonist, for Parkinson's disease are being used.
Among the 3-Alkenyl-oxindoles, compounds with trisubstituted 3-alkenyl unit were found scarcely. The first naturally occurring 3-Alkenyl-oxindoles to be isolated were (E)- and (Z)-3-(3′-methyl-2′-butenylidene)-2-indoline-ones 1. These two yellow pigments were isolated from the rhizomes of cimicifuga dahurica, a plant used in Chinese traditional medicine. In 1993, three new oxindole alkaloids neolaugerine 2, isolaugerine 3, and 15-hydroxy-isolaugerine 4, isolated from roots of Neolaugeria resinosa.

The wide range of biological activities displayed by 3-alkenyl-oxindoles has stimulated considerable pharmaceutical interest. The most successful example is sunitinib 5, which is currently prescribed for the treatment of renal cell sarcoma and gastrointestinal stromal tumours and is undergoing clinical trials studies for the treatment of other solid tumours. A number of related sutent related compound like semaxanib 6, ST280 7, ST458 8 and Tenidap 9 were developed and tested for their effeciencies.

Though a large number of 3-alkenyl oxindoles with diverse structural features were known, there are only few C-5 substituted oxindoles that have been reported till now. The biologically active compounds such as SU9516 10, GW5074 11, NP506 12, CDK2 antagonist 13, JK3 antagonist 14 were found to have C-5 substituted-3-alkenyl oxindole motif.

Owing to the importance of 3-alkenyl oxindoles, several research groups have aimed towards identification and development of more potent oxindole derivatives with diverse structural and functional variations at specified positions. Therefore, the synthesis of newly substituted oxindole derivatives that generate new molecular entities is great interest. There are different methods for C-5 substitution of oxindoles such as bromination, nitration, acylation etc., by which the target compounds can be prepared in one or multiple steps. However, the synthetic methods for direct C-5 alkylation of oxindoles are not known or very limited in the literature. In recent years, green and atom-economy synthetic approach is gaining much attention and is practiced to generate eco-friendly protocols. In this direction, use of alcohols as alkylating agents is a simple and viable method since they generate only water as a by-product in the reaction. The availability and the ease of preparation also make them an effective reaction source. Specifically, activated alcohols are more effective and significant due to the stability of corresponding carbonations. The utility of alcohols as alkylating agents in several C—C, C—N and C—O bond formations has been demonstrated under different reaction conditions. 3-alkenyl oxindole compounds that are developed and tested for different biological properties are mentioned in the patents, U.S. Pat. Nos. 4,438,130; 4,588,591; WO1993021185; WO2008133273; U.S. Pat. Nos. 8,119,652; 7,235,563; WO2001066546; U.S. Pat. No. 6,114,300. Based on the present state of art, the design, synthesis and development of 3-alkenyl oxindoles with C-5 substitution employing an eco-friendly protocol and using alcohol as the reaction source is of considerable interest.